Computation Efficient Attribute Based Broadcast Group Key Management for Secure Document Access in Public Cloud

An efficient fine-grained encryption-based access control scheme for documents stored in the public cloud network proposed by Mohamed et al utilizes more computational and storage complexities. Although, Mohamed et al.'s broadcast key management scheme communicates group key securely, it consumes massive computational and storage resources for frequently changing the group key. In order to avoid these problems, we have proposed a new broadcast group key management scheme that takes reduced computational resources by performing minimal cryptographic operations in the data owner and cloud user’s to update and recover the group key using a matrix called access control vector. The computation complexity of the data owner is reduced by performing simple arithmetic operations for updating the group key. Moreover, the computational complexity of the cloud user is also minimized by performing only one addition and two subtraction operations whenever there is a change in the group or access control policy. In addition, the proposed scheme also minimizes the storage complexity of cloud users, but maintains the same communication complexity as that of Mohamed et al.'s scheme. The performance results show that the proposed scheme is computationally efficient in the data owner and the